Summary Box: Feds scrutinize personal DNA tests

GENETIC PROBE: The Government Accountability Office submitted DNA samples from five staffers to four different genetic testing companies. The companies' results contradicted each other nearly 70 percent of the time for the same diseases, according to GAO.

TEST MAKERS RESPOND: Company executives told investigators the results differed because each company uses different standards to analyze DNA. They are currently beginning work to standardize their methods.